Many of the most exciting concepts in biology, including selection and neutrality, asexual and sexual reproduction, stochastic and deterministic dynamics, and the interplay of ecology and evolution can be studied through the lens of host-pathogen interactions. Some of the best studied pathogens are viruses that infect humans, although research has focused disproportionately on a few viruses that constitute only a small fraction of the infectious disease burden on humans. The aim of this working group is to broaden our perspective on host-pathogen interactions by synthesizing observations of the evolution of the most prevalent human viruses and asking whether commonalities and differences between evolutionary patterns can be readily explained by current theory. In particular, we will seek to augment the traditional emphasis on genotype and sequence-level analysis with information on viral phenotypes. We will also investigate whether the phylodynamic framework, which proposes that viral phylogenies are chiefly shaped by immune pressure and epidemic dynamics, provides a good approximation of the dominant evolutionary modes of less well studied viruses. Our findings will help identify gaps in the study of viral evolution and aggregate observations for the development and testing of theory.